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COMSOL Multiphysics® 6.2 Release Highlights

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RF Module Updates

For users of the RF Module, COMSOL Multiphysics® version 6.2 introduces a new feature for efficient simulation of braided cable shields, a new material model for PCB substrates, and performance improvements to the Electromagnetic Waves, Boundary Elements interface. Learn more about these updates below.

New Boundary Condition Added to the Electromagnetic Waves, Frequency Domain Interface

A new Cable Shield feature has been integrated into the Electromagnetic Waves, Frequency Domain interface. This feature enables efficient simulation of intricate shields, such as braided or perforated types, using a streamlined boundary condition that reduces computational demands.

Three spool models showing varying levels of braided cable shielding.
A braided shield (based on the Vance model) modeled using the Cable Shield boundary condition.

Performance Improvements for the Electromagnetic Waves, Boundary Elements Interface

In the settings for the Electromagnetic Waves, Boundary Elements interface, it is now possible to select symmetry planes to reduce computation time. The symmetry settings also control the far-field calculations and physics-controlled meshing. The new RCS of a Metallic Sphere Using the Boundary Element Method (RF) model showcases this functionality.

Furthermore, boundary element method (BEM) simulations on clusters are up to 2.5 times faster than in previous versions. If you also include the effect of reducing the model using a symmetry plane, then simulation times are up to 4 times faster. Additionally, the load and memory balancing for BEM models running on clusters has been significantly improved.

An airplane model showing the bistatic radar cross section in the Thermal Wave color table.
Frontal-aspect, bistatic radar-cross-section (RCS) calculation using a half-size model supported by a perfect magnetic conductor (PMC) symmetry plane.

New and Improved Features in the Electromagnetic Waves, Boundary Elements Interface

The Impedance Boundary Condition and the Layered Impedance Boundary Condition have been added to the Electromagnetic Waves, Boundary Elements interface. These boundary conditions handle metallic exterior domains and metallic exterior domains covered by a layered structure, respectively. You can view this new addition in the Modeling of Dipole Antenna Array Using the Boundary Element Method tutorial model.

The default feature, Wave Equation, Electric, now includes all standard Electric displacement field model options, such as Relative permittivity, Refractive index, Dielectric loss, etc. This simplifies the use of different materials, supporting different material models.

The COMSOL Multiphysics UI showing the Model Builder with the Impedance Boundary Condition node highlighted, the corresponding Settings window, and a dipole antenna array model in the Graphics windows.
To characterize the metallic surfaces of a dipole antenna array with finite conductivity, the Impedance Boundary Condition is applied.

View screenshot

New Electric Displacement Field Model

For the Electromagnetic Waves, Frequency Domain interface and Electromagnetic Waves, Boundary Elements interface, a new electric field displacement model, Wideband Debye model, is available in the Wave Equation, Electric feature. This model can be used to accurately describe losses and dispersive effects in PCB substrates.

The COMSOL Multiphysics UI showing the Model Builder with the Wave Equation, Electric node highlighted, the corresponding Settings window, and two Graphics windows with 1D plots depicting the relative permittivity and the loss tangent values of a material, respectively.
The relative permittivity and loss tangent values of a material, evaluated over a range from 10 Hz to 10 GHz, are characterized using the Wideband Debye electric field displacement model.

Electrical Conductivity Added to Drude–Lorentz and Debye Dispersion Models

The Drude–Lorentz and the Debye dispersion models now have additional flexibility, allowing separate input of the electrical conductivity.

View screenshot

Higher-Order Elements

In this version, up to seventh-order curl elements can now be used in the Electromagnetic Waves, Frequency Domain interface and the Electromagnetic Waves, Transient interface.

View screenshot

Cyclic Symmetry for Periodic Condition

Cyclic symmetry has been added as a periodicity option to the Periodic Condition feature. This option provides the ability to perform simulations of one sector of a full, cyclically symmetric model as opposed to the full model, reducing computation time.

The COMSOL Multiphysics UI showing the Model Builder with the Periodic Condition node highlighted, the corresponding Settings window with the Cyclic symmetry periodicity option selected, and cyclically arranged electric dipoles in the Graphics window.
The electric field in the radial direction for cyclically arranged electric dipoles. The left plot shows the full solution, and the middle plot shows a full revolution of the simulation results for only one sector (the rightmost plot). A sector dataset was used in the middle plot to accomplish the data generation.

Time-Domain Physics-Controlled Mesh

The time-domain interfaces, Electromagnetic Waves, Transient and Electromagnetic Waves, Time Explicit, now provide physics-controlled mesh suggestions based on the frequency or wavelength content of a simulation. The following tutorial models showcase this new update:

The COMSOL Multiphysics UI showing the Model Builder with the Mesh node highlighted, the corresponding Settings window with the frequency mesh element size option selected, and a dual-band antenna model in the Graphics window.
The maximum mesh size is determined by the frequency of primary interest.

Hexagonal Uniform Array Factor

The hexagonal uniform array factor quickly estimates the far-field pattern of antenna arrays on a triangular grid. In version 6.2, the hexagonal antenna arrays provide lower sidelobes, more robust performance with better resolution, lower spatial noise, and wider coverage.

Two uniform hexagonal antenna models showing the far-field pattern in the Thermal Wave color table.
A 169-element antenna array can be estimated quickly by a periodic unit cell model combined with the new hexagonal uniform array factor.

Instantaneous Norm Variables for Vector Quantities

There are new variables that can be added to the form phys.normXi = sqrt(real(Xx)^2+real(Xy)^2+real(Xz)^2), where phys is a placeholder for any physics tag, such as ewfd, and X is a placeholder for a physical quantity, such as an electric field (E), magnetic field (H), etc. These variables are especially useful when visualizing time-harmonic vector waves.

 
The instantaneous norm of surface current density (left) on a curved metallic surface provides a more dynamic visualization of wave behavior compared to the conventional norm definition (right).

User-Defined Surface Impedance

In the Impedance Boundary Condition feature and the Layered Impedance Boundary Condition feature, it is now possible to directly enter a surface impedance. Previously, the surface impedance was calculated indirectly from the material properties defined on the boundary or in the feature settings. This simplifies the modeling process for problems where it is less relevant to use actual materials for modeling the exterior domain.

View screenshot

Automatic Path Parameterization for Lightning and Electrostatic Discharge (ESD) Applications

The Edge Current feature in the Electromagnetic Waves, Transient interface can adaptively determine a parameterized path based on the selected geometry's unique shape. This enhancement simplifies the modeling process for lightning and ESD applications. View this feature in the following tutorial models:

The COMSOL Multiphysics UI showing the Model Builder with the Edge Current node highlighted, the corresponding Settings window, and an airplane model in the Graphics window.
In the Edge Current feature, the parameterized path of an arbitrary shape of a lightning channel is set to be automatic.

Reference-Edge Controlled Lumped Port Type

The Lumped Port feature now includes a Reference-edge controlled type. This option can be used to designate extra edge selections, ensuring the proper direction of voltage flow between two conductive boundaries where a lumped port is positioned.

The COMSOL Multiphysics UI showing the Model Builder with the Lumped Port node highlighted, the corresponding Settings window with the Reference-edge controlled option selected, and a dipole antenna model in the Graphics window.
The direction of the arrows in auxiliary selection helps users verify the direction of voltage flow before computation.

Enhanced Material Options for Millimeter-Wave Applications

The RF material library has been expanded to include:

  • Alumina Ribbon Ceramic from Corning Incorporated
  • WavePro® WP025LDf, WavePro® WP025, WavePro® WP030, WavePro® WP050, WavePro® WP108, WavePro® WP120, and WavePro® WP150 from Garlock
  • Radix™ Printable Dielectric by Rogers Corporation
  • Zetamix Ɛ Filaments, White Zirconia Zetamix Filament, and Alumina Zetamix Filament, sourced from Zetamix

View screenshot

A Fresnel lens model showing the far-field pattern in the Thermal Wave and Rainbow Light color tables.
Radiation pattern from a Fresnel lens, driven by a circular horn antenna, using Zetamix Ɛ Filament Ɛ=2.2 as the lens material.

A gray porous gyroid model showing the dielectric effect in the Rainbow color table.
Controllable effective dielectric constant through gyroid structures. By employing Radix™ Printable Dielectric with a relative permittivity of 2.8, a permittivity value of 1.5 can be attained in the provided porous design.

An aperture antenna model showing the enhanced gain in the Thermal Wave color table.
Enhanced gain of an aperture antenna using a ceramic-filled polytetrafluoroethylene (PTFE) dielectric lens, crafted from the WavePro® WP025LDf low-loss dielectric material.

Assessment of Specific Absorption Rate (SAR) for 1-g and 10-g Mass

In the Electromagnetic Waves, Frequency Domain interface, the Specific Absorption Rate feature has been extended for modeling of electromagnetic interactions with biological tissue. After computation, this feature provides predefined SAR results variables for tissue exposure. These variables represent SAR values for 1 g and 10 g of tissue mass and are commonly employed in industrial applications to measure radiation exposure levels. The SAR of a Human Head Next to a Wi-Fi Antenna model showcases this new update.

The COMSOL Multiphysics UI showing the Model Builder with the Specific Absorption Rate node highlighted, the corresponding Settings window, and a human head model in the Graphics window.
The Specific Absorption Rate feature provides predefined results variables to visualize and assess both SAR 1 g and SAR 10 g.

New Tutorial Models

COMSOL Multiphysics® version 6.2 brings the following new tutorial models to the RF Module.

RCS of a Metallic Sphere Using the Boundary Element Method

A metallic sphere model showing the electric field of a wave incident in the Thermal Wave color table.
The electric field of a wave incident, scattered around a metallic sphere. Only the sphere boundary needs to be meshed, as the problem is solved using the Electromagnetic Waves, Boundary Elements interface.

Application Library Title:
rcs_sphere_bem
Download from the Application Gallery

Lightning Surge on a Power Transmission Tower

A power transmission model showing the voltage effects of a lightning strike on the connected power lines in the Thermal color table.
Lightning carrying a current of 10 kA strikes one of the tower’s shielded wires. The induced voltage on the three-phase conductors is computed through rigorous simulation techniques.

Application Library Title:
lightning_surge_tower
Download from the Application Gallery

Lightning Surge Analysis of an Offshore Wind Farm

A wind farm model showing the electrical effects of a lightning strike on the field of turbines in the Thermal Wave color table.
This model examines the effects of a lightning strike on a turbine and the consequent induced electric fields on neighboring turbines. This aids in understanding the potential implications of lightning strikes on interconnected turbines in an offshore wind farm.

Application Library Title:
lightning_surge_wind_farm
Download from the Application Gallery

Modeling of a Dipole Antenna Array Using the Boundary Element Method

A dipole antenna array model showing the radiation pattern in the Thermal color table.
Radiation pattern of a 12x1 dipole antenna array. Only the surfaces of the metallic radiators are modeled using the boundary element method.

Application Library Title:
dipole_antenna_array
Download from the Application Gallery

WavePro is a registered trademark of Garlock Sealing Technologies LLC. Radix is a trademark of Rogers Corporation or one of its subsidiaries. Zetamix is a registered trademark of NANOE SAS.